Analytical devices often require dilution of samples, such as biological fluids, within certain concentration levels based on an analytical sensitivity range for a device. Digital microfluidics allows for manipulation of discrete volumes of fluids, including electrically moving, mixing, and splitting droplets of fluid disposed in a gap between two surfaces, at least one of the surfaces of which includes an electrode array coated with a hydrophobic and/or a dielectric material. Dilutions performed using a digital microfluidic device are typically serial dilutions, which involve merging sample droplets with diluent droplets having a substantially equal volumes and splitting the combined droplet to achieve a dilution ratio. Serial dilutions often create droplets that are large and difficult to manipulate, thereby increasing imprecisions during the dilution process. Serial dilutions are also limited with respect to dilution ratios that can be achieved and require repetitive steps of merging and splitting droplets to obtain a target dilution ratio.
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